* Byungchul Park <byungchul.park@xxxxxxx> wrote: > On Wed, Oct 18, 2017 at 12:09:44PM +0200, Ingo Molnar wrote: > > BTW., have you attempted limiting the depth of the stack traces? I suspect more > > than 2-4 are rarely required to disambiguate the calling context. > > I did it for you. Let me show you the result. > > 1. No lockdep: 2.756558155 seconds time elapsed ( +- 0.09% ) > 2. Lockdep: 2.968710420 seconds time elapsed ( +- 0.12% ) > 3. Lockdep + Crossrelease 5 entries: 3.153839636 seconds time elapsed ( +- 0.31% ) > 4. Lockdep + Crossrelease 3 entries: 3.137205534 seconds time elapsed ( +- 0.87% ) > 5. Lockdep + Crossrelease + This patch: 2.963669551 seconds time elapsed ( +- 0.11% ) I think the lockdep + crossrelease + full-stack numbers are missing? But yeah, looks like single-entry-stacktrace crossrelease only has a +0.2% performance cost (with 0.1% noise), while lockdep itself has a +7.7% cost. That's very reasonable and we can keep the single-entry cross-release feature enabled by default as part of CONFIG_PROVE_LOCKING=y - assuming all the crashes and false positives are fixed by the next merge window. Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
